Conventionally, a substrate working device including a plurality of substrate working tables has been known (for example, Japanese Patent Application Laid-open No. 2009-70867).
Japanese Patent Application Laid-open No. 2009-70867 discloses a printing device (substrate working device) including two substrate working tables and two printing work units, wherein a solder paste is printed, via a mask, on a substrate held by the substrate working table. The printing device includes two substrate working tables aligned in the depth direction orthogonal to the substrate feed direction (lateral direction). The substrate working tables are movable in the depth direction separately by threaded shaft driving. The substrate working tables respectively receive a substrate from the upstream side of the feed direction, and, after solder printing work by the printing work unit, carries the printed substrate out of the substrate working table in an exit position (middle portion in the depth direction) between the two substrate working tables. The printing device performs printing work with respect to a substrate held by each substrate working table in parallel, and performs substrate discharging alternately from each substrate working table in the exit position.
In the conventional printing device, there are cases where the two substrate working tables approach each other in the depth direction, such as in the case where a substrate is discharged in the exit position. Therefore, it is necessary to program the operation of each substrate working table in advance such that the respective substrate working tables do not interfere with each other. However, in reality, there are cases where a position displacement occurs due to thermal expansion of the threaded shaft for driving the substrate working table or a coordinate value of a drive motor (coordinate value used for operation control of the substrate working table) differs from the actual position due to assembly error or the like in each unit of the substrate working table. In such cases, there is a possibility that the two substrate working tables mutually interfere.
Japanese Patent Application Laid-open No. 2009-70867 does not disclose anything about such mutual interference of the substrate working tables, and there is a problem that whether or not the two substrate working tables mutually interfere cannot be determined accurately.